Orange Marmalade

Preparation

1. Step 1

   Juice the oranges into a liquid measuring cup and place the spent peels, as well as any pulp and membrane caught on the juicer, into a large (7½- to 8-quart) Dutch oven or other heavy pot (see Tip). You should have about 1¼ cups of juice; if you have more, save the excess for another use. Juice the lemons into a small bowl, reserving ¼ cup plus 3 tablespoons of the juice and adding the spent peels to the pot. Cover and refrigerate the containers of juice until needed the next day.

2. Step 2

   Cover the peels with 14 to 16 cups of water (enough so the peels freely bob). Bring to a boil, then reduce the heat to maintain a simmer. Cover the pot and cook until the tip of a paring knife can pierce the peels very easily, about 1 hour.

3. Step 3

   Remove the pot from the heat and let the peels cool and steep in the pectin-rich liquid, covered, at room temperature for 12 to 24 hours. Meanwhile, place three small plates in the freezer; you will use these to test the set of the marmalade tomorrow, and you want them to be truly ice-cold (see Tip).

4. Step 4

   Uncover the pot and retrieve the peels, gently squeezing them so any liquid falls back into the pot. (The liquid on your hands should have a greasiness to it; that is the pectin.) Cut each orange peel half in half again to make two quarters. Using a small spoon, gently scrape the membranes and most of the pith from each quarter back into the pot, leaving behind a clean, smooth piece of peel with a thin, even layer of pith attached; place the peels on a cutting board. Slice the orange peels into whatever thickness you prefer (a ¼-inch thickness is classic, but you can go super thin or cut them into a small dice instead). Alternatively, transfer the scraped orange peels to a food processor and pulse a few times to make smaller, irregular pieces.

5. Step 5

   Squeeze out any juice from the lemon peels back into the pot and discard the lemon peels.

6. Step 6

   Set a fine-mesh sieve over a large bowl and strain the contents of the pot; reserve the pot. Use a spoon to stir and press the solids into the sieve repeatedly until they break down into a dry, applesauce-like paste. Look at the underside of the sieve: You should see lots of gel-like goop. That is more pectin, and you want it in the marmalade, so use the spoon to scrape the pectin into the strained liquid. Discard the solids in the sieve and pour the orange juice from Step 1 through the sieve into the bowl too, to rinse off any remaining pectin.

7. Step 7

   Pour the strained liquid back into the pot. Set it over high heat and bring to a boil. Once the liquid is boiling, slowly pour in the sugar while stirring until it is dissolved. Add the cut orange peels, the reserved lemon juice and the salt. Return the mixture to boil over high heat, then reduce the heat to medium-high so it still boils but not as violently.

8. Step 8

   Let the marmalade cook for about 20 minutes. As it boils, it may foam up wildly. Using a slotted spoon, repeatedly scoop the top of the foam into the center of the pot to keep the foam from boiling over the side of the pot. You may also need to adjust the heat to keep the liquid from boiling over.

9. Step 9

   At the 20-minute mark, remove the pot from the heat, let the marmalade settle down, then spoon a blob of peels and liquid onto one of the frozen plates. Return the plate to the freezer for 1 minute. Remove the plate and push your finger through the liquid. If the liquid wrinkles and clings to the transparent peels in a jellylike coating, the marmalade is ready. If it’s still too loose, return the pot of marmalade to the heat, bring to a boil, then cook for 2 minutes more. Remove the pot from the heat and check the set again. Repeat until the marmalade is done. (If you want extra insurance, use a candy thermometer: When the temperature of the marmalade is 218 to 221 degrees, test it on the frozen plates.)

10. Step 10

    Once the marmalade is done, remove the pot from the heat and let the marmalade settle for 5 minutes. Use a large spoon to skim off any foam on the top. (This is not necessary, but helps produce a crystal-clear marmalade.) If storing in jars, use a ladle to transfer the hot marmalade into clean glass jars of any size, though 8-ounce jars are the most sensible. Cover with lids, let cool to room temperature, then store the marmalade in the refrigerator. (Canning the jam will lengthen its shelf life. Follow this guide for instructions on how to safely do this extra step.)